THE CHICKEN HMG-17 GENE IS DISPENSABLE FOR CELL-GROWTH IN-VITRO

HMG-17 is a highly conserved and ubiquitous nonhistone chromosomal pro tein that binds to nucleosome core particles, HMG-17 and HMG-14 form a family of chromosomal proteins that have been reported to bind prefer entially to regions of active chromatin structure. To study the functi onal role of the single-copy chicken HMG-17 gene, null mutants were ge nerated by targeted gene disruption in a chicken lymphoid cell line, D T40. Heterozygous and homozygous null mutant cell lines were generated by two independent selection strategies, Heterozygous null mutant lin es produced about half the normal level of HMG-17 protein, and homozyg ous null lines produced no detectable HMG-17. No significant changes i n cell phenotype were observed in cells harboring either singly or dou bly disrupted HMG-17 genes, and no compensatory changes in HMG-14 or h istone protein levels were observed. It is concluded that HMG-17 prote in is not required for normal growth of avian cell lines in vitro, nor does the absence of HMG-17 protein lead to any major changes in cellu lar phenotype, at least in lymphoid cells.